Mineralization of cefoperazone in acid medium by the microwave discharge electrodeless lamp irradiated photoelectro-Fenton using a RuO 2 /Ti or boron-doped diamond anode.

The mineralization of 125 mL of 50-300 mg L ^-1 cefoperazone (CFPZ) has been comparatively studied by electrochemical advanced oxidation processes (EAOPs) like anodic oxidation (AO), electro-Fenton (EF) and photoelectro-Fenton (PEF) with a RuO ₂ /Ti or boron-doped diamond (BDD) anode and an activated carbon fiber (ACF) cathode. A microwave discharge electrodeless lamp (MDEL) was used as the UV source in PEF process. CFPZ decays always followed pseudo-first-order kinetics and their constant rates increased in the order: AO < EF < MDEL-PEF, regardless of anode types. Higher mineralization was achieved in all methods using BDD instead of RuO ₂ /Ti, while the most potent BDD-MDEL-PEF gave 88% mineralization under its optimum conditions of 0.36 A, pH 3.0 and 1.0 mmol L ^-1 Fe ²⁺ . The synergistic mechanisms were explored by quantifying the electrogenerated H ₂ O ₂ and formed ^• OH, in which 2.27 and 2.58 mmol L ^-1 H ₂ O ₂ were accumulated in AO-H ₂ O ₂ with RuO ₂ /Ti or BDD anode, respectively, while 92.0 and 263.5 μmol L ^{-1 •} OH were generated in EF with RuO ₂ /Ti or BDD anode, respectively. The oxidation power of EAOPs with different anodes was also compared by measuring the evolutions of NO ₃ ^- and NH ₄ ⁺ as well as four generated carboxylic acids including oxalic, oxamic, formic and fumaric acids.
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